Patent Document 1 discloses, as an intake control device configured as described above, an intake control device that is provided with a valve body (control flap 3 in the document) that opens and closes with the rotation of a shaft (pivot shaft 9 in the document) at a position near a flange surface connected to a cylinder head in an intake manifold (inlet duct 2 in the document). As a result of the valve body being set to an open position shown in FIG. 1 or 4, the valve body is fitted within a recess portion of the intake manifold so as to maximize the opening area of the intake manifold. Also, as a result of the valve body being set to a restriction position shown in FIG. 2 or 5 by the rotation of the shaft, the valve body is displaced to a position in which the valve body rises inside the intake manifold so as to minimize the opening area.
Also, Patent Document 2 discloses a device provided with a valve body (Klappen 8 in the document) that swings about a shaft (Klappenschwenkachse 12 in the document) as in Patent Document 1. This valve body is fitted to the inner surface of the intake manifold as a result of being set to an open position shown in FIG. 6, so as to maximize the opening area of the intake manifold. Also, as a result of the valve body being set to a restriction position shown in FIG. 5, the valve body is displaced to a position in which the valve body rises inside the intake manifold so as to minimize the opening area.
Furthermore, Patent Document 3 discloses an intake control device having a configuration in which a control unit 3 is fitted at a position near a cylinder head 1 of an intake manifold 2. A valve body (control valve 41 in the document) disclosed in Patent Document 3 has the same operative configuration as that disclosed in Patent Documents 1 and 2, but is characteristic in that the control unit 3 is included in the intake manifold 2.
In other words, the intake manifold 2 includes a first member 2a that is held against the cylinder head 1 and a second member 2b that is connected to the first member 2a. The control unit 3 includes a plate-shaped valve body that is opened and closed about a pivotal axis 41 with respect to a cylindrical housing 6. With this configuration, the valve body is installed in the intake manifold 2 by fitting the housing 6 of the control unit 3 into the first member 2a and thereafter connecting the second member 2b to the first member 2a. 